1. Field of the Invention
The present invention relates to a method for containing hazardous, radioactive or mixed waste materials, and in particular, to compositions of acrylic emulsions containing a thixotropic agent, vinyl acetate-ethylene copolymer emulsions containing a thixotropic agent, or vinyl chloride copolymer latices containing a thixotropic agent which can be sprayed over, or otherwise applied to, contaminated areas to generate a flexible film or foam which entraps and immobilizes the hazardous, radioactive or mixed materials therein.
2. Description of the Prior Art
Most of the prior art for containment of hazardous waste materials utilizes compositions of natural and synthetic rubbers, silicates, or alkanolamines to provide solid masses containing the waste material. For example, U.S. Pat. No. 2,577,514, issued Dec. 4, 1951, to J. De Ment, discloses a method whereby certain reactive compounds of silicon are employed to react with the soluble radioactive compounds to form substantially insoluble derivatives thereof. The composition includes a soluble sodium silicate, dilute hydrochloric acid which forms silicic acid, and then water is utilized to wash away the reaction products and radioactive contaminants carried therein.
U.S. Pat. No. 3,063,873, issued Nov. 13, 1962, to J. R. Saroyan, discloses a protective coating composition which is applied to a surface prior to contamination to form a dried film covering the surface. After contamination, the coating can be washed off by steam or hot water which carries with it the radioactive particles embedded therein. The coating composition is a high polymer plastic of either the elastomeric (natural and synthetic rubbers) or the thermoplastic type (bitumins, vinyls, polystyrene, polyethylene, acrylics, silicones, celluloses, and polyamides) formulated with a water sensitive adhesion modifier of a hydrophilic film forming material. The process comprises applying a substantial layer of an alkali-sensitive coating composition formed of a polymer resin, ammonium hydroxide, water, and pine oil, and then washing the coating off with an alkali solution after contamination.
Prior art references which disclose the use of urea-formaldehyde solutions for containment of hazardous waste materials are all directed to forming a solid mass which contains the hazardous materials and can be disposed of by burying. However, present EPA regulations prohibit the use of urea-formaldehyde resins for this purpose due to the carcinogenic nature thereof.